Auto Laundry News - July 2013

Protection — Is it Possible to Have Too Much?

By Robert Roman

Protection is an important aspect of professional car washing because it implies durability, longevity, and added value. Operators offer motorists vehicle protection with spray, hand, or machine-applied wax. Extended protection is provided with paint sealants.

Natural wax and synthetics provide gloss, shine, smoothness, and a sacrificial barrier that traps dirt and is removed during washing. Spray products work by interfering with negatively charged water molecules’ tendency to attach to a vehicle’s surface.

The formation of negatively charged water drops happens when water is sprayed. Research shows tiny water drops that form near waterfalls, through operational spray (e.g., a fountain), or through splashing water by hand carry a negative electrical charge.

Experiments show a falling water drop is shaped like a pear – thick part down, narrow tail up. As the drop falls, pieces tear off from the tail to form many smaller drops. As this happens, droplets take away a portion of the electron charge from the big drop.

As a big water drop falls, it can acquire smaller droplets that have less velocity and are absorbed by the bigger drop, giving up their mass and charge to it.

When a water drop (and air pollution absorbed) strikes a surface, the result depends on the contact angle the drop makes with surface. A contact angle of zero degrees would result in a complete wetting of the surface. An angle of 180 degrees would result in complete repulsion of the liquid by the surface.

Water has a small contact angle on hydrophilic (water-loving) surfaces like window glass (5 to 25 degrees) and a larger angle on hydrophobic (water-hating) surfaces like silicon (70 degrees) and polymer (100 degrees).

This is why car wash operators apply drying agent and spray wax containing these substances in the wash bay. The negative charge they impart to the surface repels water molecules. The visual effect is that water beads-up and rolls off the car. Paint sealant works similarly.

First, a positively charged surface is created by applying a chemical and then negatively charged polymer- or Teflon-infused substance is applied which sticks to the positive surface. The longevity of sealant is a function of oxidization, dirt and wind abrasion, UV, and washing.

Thus, the protection car wash operators sell motorist in a wash bay is the modification of surfaces by the manipulation of the electrical charge on those surfaces.

Today, automakers look to the refinement of the Lotus Effect (LE) in industrial products and processes such as paint, window glass, and fabrics. LE is the self-cleaning properties of the lotus plant leaf. The nano-scale or microscopic structure and surface chemistry of this leaf creates a contact angle of 150 degrees and forces drops of water to roll off the surface removing dirt.

Arguably, consumers would be accepting of LE vehicle paint, car wash operators not so much. For example, a car that doesn’t require as much washing and little additional protection could cost operators considerable wash revenues. Or would it?

Scientists are closer to perfecting LE vehicle paint. However, such paint must pass tests without demonstrating detrimental effects on other desirable properties such as color selection, texture, durability, initial price, repair cost, etc. In the meantime, new ideas for creating easy-to-clean surfaces based on nano and sol-gel technology have come to market.

The benchmark for nano-coating vehicles (waterless car wash) is an efficiency of between 10 and 15 ml/m. A 250-ml bottle (8.5 ounces) costs $13 to $20. Sol-gel is a coating process that takes about 2 ounces of product ($25) to create a second, thin clear-coat layer on a vehicle. Sol-gel holds up for about eight months or roughly the same timeframe as premium paint sealant.

It is unlikely the car wash industry will collapse from nano car wash products (and MLM) or from professionally applied sol-gel coatings. LE is still distant. What is likely though is car wash operators will need to look again at what services they offer customers and how they price them.